TaskPane not working in New Outlook

[MonkeyLike-Lab]

Provide required information needed to triage your issue

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: ______ PC Desktop

• Host [Excel, Word, PowerPoint, etc.]: ______ New Outlook

• Office version number: ______
  Microsoft Outlook Version: 1.2025.109.100 (Production)
  Client Version: 20250110003.17
  WebView2 Version: 132.0.2957.115
  Session ID: d5c8ffc8-51f0-244b-bb82-bda3617b392b
  Release Channel: Targeted Release

• Operating System: ______ Windows 11 ( Latest Updates )

• Browser (if using Office on the web): ______

Expected behavior

Clicking on Add-in should open TaskPane

Current behavior

Nothing happens - taskpane is not opening.

Taskpane works in Outlook WEB, Outlook Classic.

I tried couple commercial plugins, and compiled some samples from OfficeDev.

They all work in Classic Outlook, and Outlook for web.

Steps to reproduce

1. ---

2. ---

3. ---

Link to live example(s)

1. ---

2. ---

3. ---

Provide additional details

1. ---

2. ---

3. ---

Context

Unable to use any taskpane based addins

Useful logs

• Console errors
• Screenshots
• Test file (if only happens on a particular file)

Thank you for taking the time to report an issue. Our triage team will respond to you in less than 72 hours. Normally, response time is <10 hours Monday through Friday. We do not triage on weekends.

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Outlook add-in is not opening for some users in new Outlook for Windows UI #4602
• Add-in task pane not opening in Outlook on the web #4075
• Taskpane Add-in is not displayed in Outlook Web App (OWA) #3408
• Add-In TaskPane cannot be opened after x time #4395
• Task Pane for OWA add-ins doesn't open for shared mailbox #4829

---

Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Solution 1:

Check if 'Optional Connected Experiences' is enabled. This setting can affect the functionality of add-ins. For more information, refer to this link: https://learn.microsoft.com/en-us/deployoffice/privacy/optional-connected-experiences.

Reference:

• Outlook add-in is not opening for some users in new Outlook for Windows UI #4602 (comment)
• Outlook add-in is not opening for some users in new Outlook for Windows UI #4602 (comment)

Solution 2:

Make a minor change to the manifest file. Specifically, change 'CustomTab' to 'OfficeTab'. This solution was confirmed to work by a user who faced a similar issue.

Reference:

• Add-in task pane not opening in Outlook on the web #4075 (comment)

[keyur32]

hi @MonkeyLike-Lab , thank you for the report. Assigning to @exextoc to investigate further this issue with New Outlook.

[megharai1302]

hey @MonkeyLike-Lab , does other task pane add-ins works for your new outlook, or is it the one specific you are trying is not working?

[microsoft-github-policy-service]

This issue has been automatically marked as stale because it is marked as needing author feedback but has not had any activity for 4 days. It will be closed if no further activity occurs within 3 days of this comment. Thank you for your interest in Office Add-ins!

[microsoft-github-policy-service]

This issue has been closed due to inactivity. Please comment if you still need assistance and we'll re-open the issue.